Substituted heterocycle fused gamma-carbolines are known to be agonists or antagonists of 5-HT2 receptors, particularly 5-HT2A and 5-HT2C receptors, in treating central nervous system disorders. These compounds have been disclosed in U.S. Pat. Nos. 6,548,493; 7,238,690; 6,552,017; 6,713,471; 7,183,282; U.S. RE39680, and U.S. RE39679, as novel compounds useful for the treatment of disorders associated with 5-HT2A receptor modulation such as obesity, anxiety, depression, psychosis, schizophrenia, sleep disorders, sexual disorders migraine, conditions associated with cephalic pain, social phobias, gastrointestinal disorders such as dysfunction of the gastrointestinal tract motility, and obesity. PCT/US08/03340 (WO 2008/112280) and U.S. application Ser. No. 10/786,935 also disclose methods of making substituted heterocycle fused gamma-carbolines and uses of these gamma-carbolines as serotonin agonists and antagonists useful for the control and prevention of central nervous system disorders such as addictive behavior and sleep disorders.
In addition, WO/2009/145900 discloses use of particular substituted heterocycle fused gamma-carbolines for the treatment of a combination of psychosis and depressive disorders as well as sleep, depressive and/or mood disorders in patients with psychosis or Parkinson's disease. In addition to disorders associated with psychosis and/or depression, this patent application discloses and claims use of these compounds at a low dose to selectively antagonize 5-HT2A receptors without affecting or minimally affecting dopamine D2 receptors, thereby useful for the treatment of sleep disorders without the side effects associated with high occupancy of the dopamine D2 pathways or side effects of other pathways (e.g., GABAA receptors) associated with convention sedative-hypnotic agents (e.g., benzodiazepines) including but not limited to the development of drug dependency, muscle hypotonia, weakness, headache, blurred vision, vertigo, nausea, vomiting, epigastric distress, diarrhea, joint pains, and chest pains. WO 2009/114181 also discloses of methods of preparing toluenesulfonic acid addition salt crystals of these substituted heterocycle fused gamma-carbolines.
Obsessive-compulsive disorder (OCD) and related disorders, have become highly prevalent and are difficult to treat. OCD is estimated to affect about 2.3% of people at some point in their lives, and during a given year, it is estimated than 1.2% of people worldwide suffer from the disorder. Half of people who suffer from OCD begin to show symptoms before the age of 20, which can seriously affect their ability to obtain an adequate and effective education. Without effective treatment, however, the disease can last for decades. The mainstay of pharmacologic OCD treatment is with selective serotonin reuptake inhibitors (SSRIs). A second line of therapy is with antipsychotic agents, such as clomipramine, risperidone, quetiapine and olanzapine. A significant number of patients either do not respond to these agents, or cannot handle the side effects caused by these agents. More recently, it has been reported that the opioid analgesic tramadol may be effective in treating OCD. Opiates operate by an entirely different pathway from traditional OCD treatment agents, so they offer the possibility of treatment for people who cannot take the traditional serotonergic agents or for whom these agents are ineffective. However, strong opiate agents can be addictive, and their use may be contraindicated in some patients. There thus remains an urgent need for new treatments for OCD and related disorders.